Magnetic characterization of nanocrystalline nickel ferrite films processed by a spin-spraying method

Highly crystalline nickel ferrite films with different chemical compositions were processed via the spin-spraying method and their morphological, structural and magnetic properties were subsequently investigated. Regardless of the chemical composition, films with variable thicknesses are constructed by 200-400 nm spherical grains grown in the direction normal to the substrate surface. Magnetization measurements show that the spinel ferrite films present a hysteretic behaviour at room temperature with a randomly oriented in-plane easy axis and an anisotropy constant K-1 approximate to 2.5 x 10(4) erg cm(-3). Furthermore, the absence of an angular dependence of the coercivity for the in-plane measurement of magnetization coupled with the 'M'-shaped angular dependence of the out-of-plane measurement, indicates that the anisotropy of this film is predominantly crystalline shape anisotropy.